Mayor Bill de Blasio grabbed an endorsement Sunday morning in his re-election bid — this time from someone once considered a possible challenger.

"Proof in the pudding is that after the disagreements on individual issues, we've come together and shared a vision for a progressive government that is fiscally responsible," de Blasio said at the press conference.

De Blasio and City Comptroller Scott Stringer are backing each other for re-election in their respective posts.

Earlier this year, Stringer was viewed as a potential Democratic rival to de Blasio.

But that changed after it became clear that investigations into the mayor and his inner circle for their fundraising activities would not lead to any charges.

Stringer and de Blasio have been at odds frequently in the past, but they said they each have the same long-term goals for the city while also holding each other's feet to the fire.

"My job is to audit city agencies, to make recommendations," Stringer said. "Sometimes the mayor says, 'I agree,' other times the mayor says, 'I disagree,' and that's also his prerogative.

"You can hold City Hall accountable, but you also have to understand that City Hall is not obligated to agree with you all the time."

"When it comes to defending the city's interests, to Albany, to the rating agencies, we've been in lockstep," de Blasio remarked on his relationship with Stringer.

The mayor has already secured endorsements by several other elected leaders and unions.

Neither Stringer or De Blasio face a major primary challenge.

Despite the mayor's strong re-election chances, he hit the campaign trail this weekend, holding a rally in the Bronx on Saturday.

He also spoke with voters on the street — kind of retail campaigning that defined his bid for City Hall four years ago but has not played as large a role this time around.

Locking up support from unions and even critics has been more important to de Blasio.

When it comes to campaigning, even politicians at odds are known to occasionally come together.